Means of radiating heat



Sept. 28, 1943.

R. A. LSELIGMAN mains OF RADIATING HEAT 3 Sfieets-Sheet 1 Filed OctINVENTOR. BY R 21)! I 47 K 7 K i, A TTORNE Y5 Sept. 28, 1943. R. A. L.SELIGMAN MEANS OF RADIATING HEAT Filed on. 12, 1940 3 Sheets Sheeo- 2INVOR. WW $3 M [07m q. ZTTCRNEY:

Sept. 28, 1943. R. A. L. same-MAN mums OF RADIATING'KHEA'I' s Sheets-Shes; 5

Filed Oct. 12, 1940 INVENTOR. M MW WQ/pfiym A TTORNEYS.

Patented Sept. 28, 1943 a ihiatt.

\ 'MEANS or RADIATING HEAT,

Roger Adolphe Leonard Seligman, Paris, France; vested in the AlienProperty Gustodian Application October 12, 1940, Serial No. 360,939

7 Claims. (Cl. 257-125) "I'his invention relates to means of radiatingheat and more especially to means for dissipating the excess heatdeveloped by airplane internal combustion engines.

Certain types of airplane engines are liquid cooled and are providedwith radiators comprising a large number of thin-wall heat-insulatingelements separated by narrow interstices mounted in the stream of airflowing past the vehicle, in order that' air flowing through theinterstices shall carry .away the heat of the liquid flowing through theradiator. Such a radiator, while effective for eliminating the excessheat of the engine, does so at an excessively large expense inv airresistance of the aircraft upon which the radiator is 'mounted.

An object of this invention is the provision of heat dissipating meansfor, andof dissipating the heat of,'an airplane engine of such characteras not to add' to the air resistance of the aircraft, g

Another object of this invention is the provision of airplane engineheat-dissipating means of such structure as not materially to increasethe weight of the aircraft above the weight of radiator structures nowin use.

A still further object of this invention is the provision of airplaneengines heat-dissipating means having provision for adjusting the rateof heat dissipation,

In many present-day airplanes, the wings are composed of sheet metal andthis invention utilizes the metal air-foil surface to effect dissipationof heat from the engine. Within a wing or elsewhere are providednumerous radiating fins in heat-conducting relation to an airfoilsurface. Suitable conduits conduct the engine cooling liquid into heatexchange relation to the fins and heat is 'dissipated from the coolingliquid through the fins and airfoil surface into the air passingoverthe'wing upon forward movement of the airplane. The air resistanceof the airplane is only that produced by the plane itself as theradiating system is entirely enclosed within the wing. Also,'the'radiator is composed merely of liquid conducting pipes andradiating fins which are of minute thickness whereby the weight of theradiating system is relatively immaterial in comparison with the totalweight of the airplane.

Other objects, novel features and advantages of this invention willbecome apparent from the following specification andaccompanyingdrawings, wherein:

Fig. 1 is a fragmentary verticalsection of an airplane equipped withheat-dissipation means embodying the invention: r

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is a section on the line 3-3 of Fig. 2;

Fig. 4 is a fragmentary vertical section similar to Fig. 1 of amodification;

Fig. 5 is a section on the line 5-5 of Fig. 4;

Fig. 6 is a section on the line 6--6 of Fig. 4;

Fig. 7 is a fragmentary section similar to Fig. 2 of a furthermodification;

Fig. 8 is a section on the line -88 of Fig. '7;

Figs. 9 and 10 are sections generally similar to Fig. 3 and showingstill further modifications;

Fig. 11 is a section through an airplane wing equipped with themodification illustrated in Fig. 9, the section-being substantially onthe line llll of Fig. 9;

Fig. 12 is a section generally similar to Fig. 3 of another furthermodification;

Fig. 13 is a partial perspective view of the structure shown in Fig. 12;r

Fig. 14 is a partial perspective-of a wing sec tion showing one mannerof installing therein a series of radiating pipes and fins. according tothe present invention.

Referring to Figs. 1, 2, 3 and 14, I0 designates a liquid cooledinternal combustion engine suitably supported in the engine cowling ofan airplane and II designates the surface of wings extending fromopposite sides of the engine. The engine is equipped with a liquidcirculating jacket having an inlet port l2 and outlet ports l3.Associated with the inlet port i2 is a pump (not shown) for effectingcirculation of liquid through the cooling jacket. A cooling pipe Mhaving preferably a number of sections extends parallel and closelyjuxtaposed to the inner face of a metallic airfoil surface ll ofthe-wing or of any other airfoil surface of the plane. The inner end ofone section of pipe I t is connected to an outlet port I 3 and the innerend of another section of pipe I4 is connected to the inlet port l2 anda continuous system of pipes M is provided so as to afford a continuousliquid path from outlet port It through the cooling zone and return toinlet port l2.

To each section'of pipe M is secured (as, by

Preferably, the radiating fins I5 are composed of sheet metal of lightweight and high heat conductivity, such as duralumin, and are of athickness less than 1% the diameter of the pipe I4. Also, preferably,the fins are spaced on centers less than twice the diameter of the pipeand the pipe is positioned not more than three diameter from the metalII, while the lateral spread of the extensions I6 is considerablygreater than the diameter of the pipe. In one form of the invention heredescribed for illustration only, the pipes I4 may be of one centimeterdiameter with Duralumin fins from 0.2 to 0.4 mm. thick and spaced apart0.33 centimeter while the extensions flare laterally for a totaldistance of? centimeters.

The sections of pipe I4 may be mounted in proper spaced relation withmetal II in any desired manner. I prefer, according to the form of theinvention here described, to secure these sections of pipe in spacedholes in the structural members 38 of the wing. It will be understoodthat adjacent sections of pipe I4 are connected by return bends 39 whichinterconnect all sections of pipe I4 into a single continuous liquidpath.

Cooling liqu d discharged from the engine jacket passes through thepipes I4 and heat from such liquid is transferred from the liquid to thefins I5. The fins conduct heat to the metal surfacing material II fromwhich it is dissipated into the air flowing over the wings.

In the modification illustrated in Figs. 4, 5, and 6, the ends ofsections of the pipes I4 may be connected by flexible hose I9 and one ormore of the pipes may be supported in blocks 20 slidably supported inchanneled brackets 2| the brackets being attached at their upper ends tothe inner surface of the metal airfoil material H and being supported attheir lower ends upon struts 23. In each bracket is mounted a helicalspring 24 to one end of which is attached one link of a toggle member25, the other link of which is attached to the block 20. A rod 26 isattached to the middle pivot of the toggle and extends along the wing tosuitable operating means (not shown) which may be actuated by theairplane pilot. With the toggle in the broken position shown in Figs. 4and 5, the blocks 20 are in such position as to provide small clearancebetween the flanges I1 and the inner surface of metal II.

These fins are, therefore, in such relation to the metal II as tomaterially reduce the dissipation of heat through these fins to metalairfoil surface II. By movement of the rod 26 to the right from theposition shown in Fig. 4, the toggle 25 is straightened out to move theblocks 20 upwardly to bring the flanges I'I into contact with the metalI I, in which position they are resiliently held by the springs 24.Thus, by mounting some, or all, sections of pipe I 4 in the mannerdescribed, the rate of heat dissipation may be controlled by the pilot.For example, if the pipe I 4 be composed of ten sections, connectedtogether by fiexible couplings, the pilot may retract any desired numberof these sections from heat transfer relationship with the metal surfaceI I. Accordingly, as more or less sections are so retrac ed, the totalrate of heat-dissipation from the pip I4 may be varied.

In the modification illustrated in Figs. 7 and 8, fin members 21 arepermanently secured; to the inner surface of th metal II by soldering orwelding, and in the lower end of each such fin member 21 there isprovided a recess 28 of rectangular cross-section. With each fin member21 is associated a fin section 29 extending into the recess 28 andslidable therein, the upper end of such section being provided with adownwardly extending notch 30. The pipes I 4 extend through apertures inthe sections 29 and are supported by vertically adjustable blocks 29,such blocks being slidably mounted in the brackets 2|. Vertical movementof the blocks 20 and the associated pipe I4 is effected by means ofalink 3| equipped with suitable pilot actuating means (not shown).

The structure illustrated in Figs. 7 and 8 provides for progressivevariation in the rate of heatdissipation under control of the pilot.With the blocks 20 in their highest position, each section 29 isinserted in its cooperating member 21 to the greatest extent and amaximum area of contact exists between them. Upon downward movement ofthe blocks, the area of contact is progressively reduced, due to thewithdrawal of the section 29 from the member 21. The area of contactdecreases along a curved line rather than a straight line because of theprovision of the notch 30 and when the section 29 is inits lowermostposition, the only area of contact is that afforded by the tip ends ofthe horns formed by the notch 30. Thus, by mounting some, or all, of thepipe sections I4 in the manner described, the minimum cross-sectionalarea of the metallic path through which heat may be conducted from pipeI4 to metal surface I I, and thus the rate of heat dissipation, may becontrolled by the pilot.

In the modification illustrated in Fig. 9, the pipes I4 are all fixedlymounted and-are equipped with fins I5, the flanges I I of eachcontacting the metallic wing surface material I I. Between each pair offins I5 are provided plates 32 of similar material and thickness havingextensions equipped with flanges permanently attached'to the wingsurface. Each of the plates 32 terminates short of the pipe I4 so thatit does not provide a direct heat-conductive path from the pipe. Theplates 32, however, derive heat from the fins I5 by air convectionacross the intervening space, the amount of heat transmitted across theair gap being under control of the pilot in the manner hereinafterdescribed.

In the modification illustrated in Fig. 10, the pipes I4 are supportedin fixed relation to the wing surface and are equipped with fins I5awhich, however, do not engage the wing surface, but terminate shortthereof. Plates 32, similar to those described in connection with Fig.9, are supported by the wing surface and are arranged in alternatingrelation to the fins I511. In this form all the heat is required to passacross an air gap and the passage thereof is under control of the pilotas set forth below.

Either of the modifications illustrated in Figs. 9 or 10 may be arrangedwith the apparatus illustrated in Fig. 11 for causing turbulence of theair between the fins or maintaining said air at rest. Such apparatus maybe of any form. As here shown, a blower 40 actuated by a motor 4| isarranged with suitable shrouding 42to circulate a current of air betweenfins I5 and 32 (Fig. 9) or fins I5a and 32 (Fig. 1.0) in such mannerthat heat radiated laterally from the fins I5 or I511 to the adjacentair is then transported by physical movement of this air by convectioncurrents to the fins 32 where it is given up by the air and is thenconducted by fins 32 to surface II for dissipation to the air-stream.Since air is not a from fin 15 or 15a to fin 32 depends chiefly uponwhetherthe .air occupying the air gap is at rest or is turbulent, andupon the degree of such turbulence. Accordingly, by controlling thespeed of the blower; 40, the degree of turbulence of the air within theair gap between fins l or l5a and 32 may be controlled. Suitable controlmecha-- nism, for instance a variable rheostat 44 under control of thepilot, may be arranged to govern the power supplied from source 45 tothe motor Al and thus control the speed of the motor and of the blower.Accordingly, means has been pro- Vided, through the motor controls, forvarying therate of transfer of heat from'the surface of pipe M to themetal plate II and thus the rate of dissipation of heat from plate M tothe air stream.

In the modification illustrated in Figs. 12 and :13, and pipes 14 areprovidedwith fins 31 extending longitudinally of the pipes. Preferably,each pipe is provided with a plurality of fins extending more or lessradially from the pipe, the fins being of progressively differing lengthto afford contact. of their outer edges with the metal airfoil surface,such fins preferably being of metal of the same thickness as the fins l5and having the same characteristics except with respect to shape andlocation.

.The foregoing modifications, as shown in Figs. 4 to 11, inclusive,permit reduction in the rate of heat-dissipationwhen'the airplane isflying in regions so cold as to require such reduction, and in each casethe amount or degree ofreduction is under control of the pilot.

In the form of device shown in Fig. 2, for example, the lateral spreadof the fins results in their being roughly triangular in generaloutline, with the base of the triangle in contact with the metal plateII and the pipe l4 located at or near that apex of the triangle which isopposite to said base. The form of device shown in Fig. 12 achieves thesame lateral spread, but as the fins run longitudinally of the pipe, theresult is to generate a prism of triangular crosssection with the basethereof in contact with the metal plate II and the pipe l4 located at ornear the apex of the prism opposite to said base.

I claim:

1. In an airplane, the combination of a metal plate having one faceadapted to be in contact with the air-stream, a multiplicity ofcloselyspaced fins of thin sheet metal secured to that face of saidplate which is opposite to the face thereof adapted to be in contactwith the airstream, a conduit for the cooling liquid of an engineadapted to transmit heat from said liquid to said fins, whereby a pathis established for the transmission of heat from the surface of saidconduit through said fins to the metal plate for dissipation by thelatter to the air-stream, and means under control of the pilot to varythe rate of transmision of heat in said path from the surface of theconduit to said metal plate.

2. In an airplane; the combination of a metal plate having one faceadapted to bein contact with the air-stream, a multiplicity ofcloselyspaced fins of thin sheet metal secured to that I face of saidplate which is opposite to the face conductivity of said path whereby tocontrol the rate of heat-dissipation to the air-stream.

3. In an airplane, the combination of a metal plate having one faceadapted to be in contact with the air-stream, a multiplicity ofcloselyspaced fins of thin sheet metal secured to that face of saidplate which is opposite to the face thereof adapted to be in contactwith the airstream, a metallic conduit forming part of the coolingsystem of an airplane engine, and means under control of the pilot tomove said conduit laterally into contact with said fins whereby toestablish a metal path through which heat may be conducted from saidpipe through said fins to the metal plate for dissipation by the latterto the air-stream and also to move said conduit out of contact with saidfins whereby to interrupt, said path for conduction of heat.

4. In an airplane, the combination of a metal- I heat-conducting pathwhereby the rate of conduction of heat from said pipe to the air-streammay be raised progressively throughout a range of conduction-rates.

5. In a radiator for use with an internal combustion engine, a metallicsurface adapted to contain heat to be dissipated, a second metallicsurface adapted to receive said heat for dissipation thereof, saidsecond surface being closely juxtaposed to said first surface and spacedapart therefrom to form a limited air-gap between them, means tomaintain the air within said airgap in a condition of substantial restwhereby to lnterpose maximum resistance to the passage of heat betweensaid surfaces, and selectively operable means adapted to create adesired degree of turbulence of the air within said air-gap whereby topermit the passage of heat between said plates by convection and thus todiminish the resistance of said gap to the passage of heat between saidsurfaces.

6. In air airplane, a metallic plate having one face adapted to be incontact with the airstream, a liquid conduit for the engine-coolingliquid, a fin of thin sheet metal secured to said conduit and adapted toreceive heat therefrom, a second fin of thin sheet metal secured to saidplate and adapted to conduct heat thereto for dissipation from saidplate to the air-stream, the said fins being closely juxtaposed inparallel relation with a limited air-gap between them, means to maintainthe air within said air-gap in a condition of substantial rest, andselectively operable means adapted to create a desired degree ofturbulence of the air within said air-gap whereby to create convectioncurrents therein for the passage of heatbetween said fins by convection.

7. In an airplane, in combination, a metal plate forming part of anairfoil surface one of whose faces is adapted to be in contact with theair-stream, a metallic conduit for the passage of site face of saidplate, a plurality of fins of thin sheet metal arranged between saidconduit and said plate and forming in part at least a path for theconduction of heat between the surface of said conduit and thelast-mentioned face of said plate, said fins being so shaped as to0ccupy a space enclosed generally by the surfaces of a prism oftriangular cross-section with the base of said prism disposed towardsaid plate and the apex of said prism opposite said base disposedadjacent the conduit, andhieans under control of the pilot to varythe'heatconductivity of said path whereby to control the rate ofheat-dissipation to the air-stream.

ROGER ADOLPHE LEONARD SELIGMAN.

